Why are cops in cities terrible?
Is it because of bad apples? ( Maybe, but even good cops still do jerk things)
Is it because they have a lot of legal protection for bad behavior (maybe, but in the US you can get some restitution, and they can get punished)
It's really because police are just giant revenue generating machines for the city.
In order for a police officer to advance in his career, he is measured by the number of citations, summons, and arrests he has achieved.
And if performance is based on the number of bad things happening in your area, all of a sudden you see bad things happening everywhere.
A police officer does not get promoted for the number of old ladies he or she helps cross the street, the number of kittens retrieved from trees, or having effective patrols that result in zero incidences. They only get promoted for getting the high stats of bad actions.
And if police departments institute quotas, then you feel compelled to find a sucker (usually a minority or poor person because they lack the resources to fight back) to harass and induce them to break a minor infraction to get them into the station or write a citation.
Take away the performance metric of citations, summons and arrests, and you will have a much better police force who is delegated to truly being servants of the community rather than the rich and powerful.